This research continues the quest towards understnding the development of social longitudinal expressions during infancy. A longitudinal study of Down's syndrome infants focuses on affect expressions and supplements a completed similar study of normal infants; its goal is to investigate developmental sequences of behavior in relation to changes in social and physiological sectors. A guiding point of view is that the development of affect can be understood more clearly if data of CNS maturation, the infant's environment, and his behavior are obtained concurrently. Alterations in normative sequences of social affective development and CNS development are being studied in the Down's infants. It is anticipated that findings will increase our understanding of normal developmental processes and have potential for preventive mental health knowledge in both Down's syndrome and normal infant families. Studies of emotional expressions include a description and analysis of dimensions and categories of messages inherent in normal infant facial expressions at different ages. Such data will be related to naturalistic context and, after normative information is obtained, deviations in signal- and receiver-operating characteristics will be delineated. Ultimately, a screening test for distortions and parental perception of infant emotional expressions will be devised. Finally, a number of studies focus on early parental interactions. Early affective deviations in Down's syndrome infants are being studied in relation to parental processes of grief and attachment. Other studies assess the effects of increased hospital contact on interactions of mothers and fathers with their newborn infants.